Corrugated steel pipe is used to provide inexpensive, yet durable conduit for water and other fluids. The corrugations give the thin walled pipe added strength and enable it to be buried in the ground. A typical application of corrugated pipe is in forming a culvert, wherein a length of corrugated pipe is buried in the ground beneath a roadway, so as to provide a drain crossing beneath the roadway. Such an application typically requires 20-30 feet of corrugated pipe.
It is desirable to supply corrugated pipe in lengths are shorter than the typical 20-30 feet lengths that are dictated by culvert or other applications. This is because shorter pipe lengths are easier and safer to handle in transport. At the job site, the shorter pipe segments are joined together at their ends to make up the required length of pipe.
In the prior art, pipe lengths are joined together with metal connecting bands. To join two pipe lengths together, the pipe lengths are butted up against each other at their ends, and the band is assembled onto the two butted ends. The band encompasses the circumference of both pipes and overlaps the ends of both pipes. The band may be corrugated so as to matingly fit around the pipes, or it may be smooth and uncorrugated. The band is then tightened.
The problem with using bands in joining pipes together is the difficulty of installing them onto pipe. Smooth connecting bands are typically provided in straight lengths. The installer must locate the band around the ends of both pipe segments and then bend the stiff steel into a circular shape to conform to the shape of the pipe. The installer then must fasten the two ends of the band together. Smooth connecting bands have very little holding capability; the two pipes can easily pull apart even after the band has been tightened. Corrugated connecting bands have greater holding capability, but are also difficult to install. Corrugated connecting bands typically are provided already formed in a circular shape. Therefore, the band must be held open around one pipe end while the other pipe end is inserted into the band. This installation process requires two installers, one of which must struggle with holding open the stiff connecting band.
Another disadvantage is that connecting bands, which are extra pieces of equipment, add to the cost of using the pipe. Furthermore, connecting bands merely serve to hold the two ends of pipe together; the bands do not impart any structural strength to the pipe.